Home Inspection State Practice Exam 2026 - Free Home Inspection Practice Questions and Study Guide

A dielectric union is specifically designed to connect dissimilar metals in plumbing, such as copper and steel. When two different types of metal are in contact with one another in the presence of an electrolyte, like water, it can lead to galvanic corrosion, which deteriorates one of the metals over time. A dielectric union incorporates a non-conductive material that separates the two metals, effectively preventing this type of corrosion.

This separation is crucial because it helps maintain the integrity of the plumbing system and extends its lifespan, ultimately reducing maintenance and replacement costs associated with corrosion damage. By using a dielectric union, plumbing systems can function safely and effectively without the risk of degrading connections due to dissimilar metal interactions.

Other options, while related to plumbing, do not capture the primary purpose of a dielectric union. Factors such as expansion and contraction, prevention of leaks, and enhancing water pressure relate to different aspects of plumbing design and function but do not address the critical issue of dissimilar metals and corrosion.